High Strength and High Ductility in Nanostructured Aluminium-Based Intermetallics Produced by High-Pressure Torsion

Kaveh Edalati; Zen Ji Horita

doi:10.4028/www.scientific.net/MSF.765.558

Paper Titles

Acoustic Emission Study of Mg-Mn Extruded Alloys with Prospective Mechanical Properties
p.537

High Temperature Mechanical Properties of Sand-Cast Mg-Gd-Y Magnesium Alloy
p.543

The Effect of Aluminium on Deformation and Twinning in Alpha Titanium: The 45° Case
p.549

Wear Behaviour of A356 Aluminium Alloy Reinforced with Micron and Nano Size SiC Particles
p.554

High Strength and High Ductility in Nanostructured Aluminium-Based Intermetallics Produced by High-Pressure Torsion
p.558

Tension-Tension Fatigue Behaviour of Carbon Nanotube Reinforced Aluminium Composites
p.563

Compressive Creep Behaviour of Extruded Mg-10Gd-3Y-0.5Zr (wt.%) Alloy
p.568

Fatigue Crack Growth in Cast and Wrought Aluminium Alloys
p.574

Reducing Mechanical Asymmetry in Wrought Magnesium Alloys
p.580

HomeMaterials Science ForumMaterials Science Forum Vol. 765High Strength and High Ductility in Nanostructured...

High Strength and High Ductility in Nanostructured Aluminium-Based Intermetallics Produced by High-Pressure Torsion

Abstract:

Aluminium-based intermetallics (aluminides) exhibit high strength, but low plasticity at room temperature. Despite approaches employed for improvement of their mechanical properties, there is a trade-off between the strength and the plasticity in intermetallics. In this study, several nanostructured aluminium-based intermetallics (AlNi, TiAl, Ni₂AlTi) with ultrahigh compressive strength, up to 3.5 GPa, and high plasticity, up to 23%, are produced in situ from elemental powders by severe plastic deformation using high-pressure torsion (HPT) at 573 K and subsequent annealing at 673 or 873 K. It is shown that the high work-hardening behavior and plasticity in these intermetallics are due to (i) nanotwin formation, (ii) bimodal microstructure, and (iii) activation of different deformation mechanisms such as dislocation slip, twinning and grain boundary sliding. The diffusivity appears to increase by 12-22 orders of magnitude during HPT because of ultrahigh vacancy concentration and high dislocation density, which results in the formation of intermetallics at low temperatures.